Open-ended wrenches have numerous applications wherever any of various rotatable elements such as hexagonal nuts or bolts need to be tightened or loosened. The open-ended variety of wrench is especially useful where tight spaces restrict the use of socket wrenches or other closed-end tools. The difficulty with these wrenches, however, is that when the user is using it to turn an element in anything but the most unrestricted of spaces, the wrench must be removed from the rotatable element and repositioned every fraction of a turn due to interference with other obstructions. Thus, without adequate space for a full 360-degree turn of the handle, multiple turning strokes must be applied, with repositioning necessary after each stroke. This shortcoming slows the rate at which the rotatable element is driven or loosened, making it difficult and sometimes nearly impossible to turn rotatable elements quickly in tight or awkward spaces.
A number of ratchetable open-ended wrenches have been developed to surmount such shortcoming. Among various ratchetable open-ended wrenches, a particularly simple useful configuration is disclosed in U.S. Pat. No. 5,533,428 (Pradelski), which is commonly controlled with the present invention. The patent discloses a wrench utilizing only two moving parts, with one of such parts simply being a spring which pushes the other, a retractable jaw member, within a slot in one of the two fixed jaws of the open-ended wrench. The retractable jaw member of the aforementioned patent enables the wrench to rotate about the rotatable element in the direction opposite to the direction of applied torque. Thus, a series of sequential partial-turn strokes can be applied to a rotatable element without removing the wrench. Much of the reactive torque force is absorbed by the wrench jaw, as opposed to the more delicate parts of the ratcheting mechanism itself.
Notwithstanding the advances in ratchetable open-ended wrenches, there remain certain problems and a need for significant improvements in performance.
One problem relates to certain common misuse and abuse of open-ended wrenches. Such wrenches, including those of the ratcheting type, are frequently used in appropriately as hammers or crowbars, and in some cases extreme torque is applied in dealing with rotatable elements (nuts, bolts, etc.). These forms of misuse put excessive stress or impact loads on one of the jaws of the wrench. Therefore, it is important that the jaws of the wrench be as strong as possible in order to prevent failure. In ratchetable open-ended wrenches, such as those of the above-mentioned patent, jaws with reduced metal structure due to the need to achieve ratcheting action (by accommodating ratcheting members) are particularly susceptible to such failures.
Another problem in prior ratchetable open-ended wrenches is the fact that their ratcheting members sometimes tend to catch or hang up on burrs or other sharp irregularities on the rotatable elements. It is desirable that the rotation of the wrench in the direction opposite to the direction of applied torque be as free as possible.
Still another problem relates to dealing with worn rotatable elements—i.e., rotatable elements with worn corners between the flats. Certain ratchetable open-ended wrenches of the prior art provide contact area inadequate to apply sufficient torque to severely worn rotatable elements. A ratchetable open-ended wrench having improved engagement with severely worn rotatable elements would be a significant advance in the art.